Do so at your own risk.
The specs for the Apple Watch 4 was to 50M. That being said, I was on vaca and it got wet on the first day of vaca. I have a 4 month old watch >$900. It was wet and couldn't be restated....totally DEAD. Just returned today and went to Apple store and even though I purchased Apple Care, they had to send it out and if water damage is found, it's $69 for the repair. The watch will have water damage, because that's when it died. I was in the water about 20 minutes, no deeper than 42" (pool's max depth).
This freaked my wife out and she never wore her watch in the water, fearing the same fate. There are other posts people with Apple Watch 4 used for swimming coming up totally dead.
This is a nightmare that doesn't need to be. If I have Apple care AND a unit that is virtually new, they should just replace it, period.